South Korean lift-offs in 2009 and 2010 failed. Two more recent launch attempts were aborted at the last minute because of technical problems.

The new attempt came amid increased tension on the Korean peninsula over North Korea's threat to explode its third nuclear device. Pyongyang is angry at tough new international sanctions over the December 12 long-range rocket launch that delivered its satellite.

The South Korean rocket blasted off from a launch pad in the south-western coastal village of Goheung.

Science officials told cheering spectators minutes later that the rocket delivered an observational satellite into orbit. There was no immediate confirmation that the satellite was operating as intended.

The launch is a culmination of years of efforts by South Korea - Asia's fourth-largest economy - to advance its space programme and cement its standing as a technology powerhouse whose semiconductors, smartphones and cars command global demand.

North Korea's long-range rocket programme, in contrast, has generated international fears that Pyongyang is getting closer to developing nuclear missiles. Washington and Seoul have called North Korea's rocket launch a cover for a test of Pyongyang's banned ballistic missile technology.

Both Koreas see the development of space programmes as crucial hallmarks of their scientific prowess and national pride, and both had high-profile failures before success.

The satellite launched by Seoul is designed to analyse weather data, measure radiation in space, gauge distances on Earth and test how effectively South Korean-made devices installed on the satellite operate in space.